Conventionally, in a coaxial connector, an inner conductor of a coaxial cable and a connection terminal of the coaxial connector are often connected together through soldering. However, if there is a change in the amount of solder used in the connection, there is a problem that the characteristic impedance is different from a desired value. Besides, since the solder includes lead in many cases, it is desirable that soldering be limited in consideration of the environmental issues at the time of disposal.
Therefore, known coaxial connectors shown in FIG. 10 and FIG. 11 are disclosed that does not use the solder in the connection between the inner conductor and the connection terminal (see JP 2002-324636 A).
As shown in FIG. 10, this known coaxial connector 101 includes an insulating portion 103, a connection terminal 102 secured to the insulating portion 103, and a metal shell 104. The connection terminal 102 is connected to an inner conductor 134 of a coaxial cable 131, and the shell 104 movably supports the connection terminal 102 using the insulating portion 103.
The connection terminal 102 includes a pair of opposing contacts 102a and 102b formed from a metal plate spring and into a letter V shape. In the pair of contacts 102a and 102b, one contact 102a is secured to the insulating portion 103. In addition, the shell 104 is composed of a shell main body 104a, a shell folding portion 104b, a first engaging tongue portion 104c, a second engaging tongue portion 104d, and a third engaging tongue portion 104e. The shell main body 104a supports an insulating portion main body 103a of the insulating portion 103. The shell folding portion 104b is arranged side by side with an insulation folding portion 103b of the insulating portion 103, and is folded together with the insulation folding portion 103b. The first engaging tongue portion 104c is provided at each side of the shell folding portion 104b. 
In the coaxial connector 101, the shell folding portion 104b and the insulation folding portion 103b are folded toward the shell main body 104a and the insulating portion main body 103a at the same time. Then, the other contact 102b included in the connection terminal 102 pushes the inner conductor 134 to one contact 102a with each of folding forces of the shell folding portion 104b and insulation folding portion 103b (see FIG. 11). Hence, the pair of the contacts 102a and 102b elastically deform and hold the inner conductor 134 of the coaxial cable 131. On the other hand, the first engaging tongue portion 104c is crimped onto the insulating portion main body 103a, and the shell main body 104a, the second engaging tongue portion 104d is crimped onto an outer conductor 133 of the coaxial cable 131. The third engaging tongue portion 104e is crimped onto an outer cover 132 of the coaxial cable 131. Accordingly, the inner conductor 134 of the coaxial cable 131 and the connection terminal 102 are electrically connected.
By employing the above configuration, it is no longer necessary to connect the inner conductor 134 to the connection terminal 102 by soldering. This solves the problem that the characteristic impedance is different from a desired value, which is caused by a variation in the used amount of the solder. This also solves the problem of the environmental issues at the time of disposal, which is brought by using the solder.
It is to be noted, however, that in the known coaxial connector described in JP 2002-324636 A, the shell folding portion 104b and the insulation folding portion 103b are folded so that the inner conductor 134 is held between the contacts 102a and 102b. Therefore, the amount of holding the inner conductor 134 is easily changeable. To be specific, the folded portions of the shell folding portion 104b and the insulation folding portion 103b change the pushing amount into the contact 102b. This easily results in variations in the amount of crimping the inner conductor 134 together with the contact 102a. If it is difficult to control the amount of holding the inner conductor 134, the connection reliability between the inner conductor 134 and the connection terminal 102 would be degraded.